1. Technical Field
This invention relates to a ceramic tile having improved abrasion resistance and a method for applying an abrasion resistant layer. Specifically, it relates to ceramic insulation tiles used in high-temperature aircraft applications to protect metallic structure from hot engine exhaust.
2. Background Art
Ceramic insulation tiles are used in aircraft applications to protect the aircraft metallic structure from high temperature engine exhaust. Current insulation tiles provide adequate protection from high temperatures, but not from the abrasion caused by high velocity engine exhaust gases and associated erodents. Because high temperature insulation tile is composed of a porous lightweight ceramic, however, abrasion is particularly damaging to the physical integrity of the ceramic tile.
For example, engine exhaust gases such as CO.sub.2, O.sub.2, CO, and unburned fuel at high flow rates can abrade and erode insulation tile. Further, abrasion can arise from airborne particulate matter related to aircraft operation such as sand, dirt, soot, engine coatings, and turbine blade particles. Therefore a means of improving the abrasion resistance of such insulation tiles to extend the life of such tiles and reduce the cost of operation of the related aircraft is required.
Current methods of increasing the abrasion resistance of insulation tiles are costly and labor intensive. For example, one method is the chemical vapor deposition of SiC onto such tiles. This approach is costly and has limited improvements in abrasion resistance. Another approach is to spray a glass frit on the tile in multiple steps. This method requires extensive training of production personnel, is costly and very labor intensive. Further, the results of this process may not be highly reproducible because of the many manually controlled steps involved in the process.
Thus, one object of the invention is to provide a ceramic insulation tile that is resistant to abrasion from the types of gas flow and erodents present in high temperature aircraft operation.
Another object of the invention is to provide an abrasion resistant ceramic insulation tile that is low in cost and can be made with a process that is not labor intensive.
Another object of the invention is to provide a process to make an abrasion resistant ceramic insulation tile that is uncomplicated and, therefore, highly reproducible. This object will also reduce the cost of the resulting tile.
A further object of the invention is to provide an abrasion resistant ceramic insulation tile that is lightweight, which object is a mission critical parameter on all modern aircraft for performance and economy of operation.